We were getting along so well…

In point of fact, to answer your question, the LCMS does teach that the office of the papacy is that of Anti- Christ.
*Of the Antichrist
As to the Antichrist we teach that the prophecies of the Holy Scriptures concerning the Antichrist, 2 Thess. 2:3-12; 1 John 2:18, have been fulfilled in the Pope of Rome and his dominion. All the features of the Antichrist as drawn in these prophecies, including the most abominable and horrible ones, for example, that the Antichrist “as God sitteth in the temple of God,” 2 Thess. 2:4; that he anathematizes the very heart of the Gospel of Christ, that is, the doctrine of the forgiveness of sins by grace alone, for Christ’s sake alone, through faith alone, without any merit or worthiness in man (Rom. 3:20-28; Gal. 2:16); that he recognizes only those as members of the Christian Church who bow to his authority; and that, like a deluge, he had inundated the whole Church with his antichristian doctrines till God revealed him through the Reformation — these very features are the outstanding characteristics of the Papacy. (Cf. Smalcald Articles, Triglot, p. 515, Paragraphs 39-41; p. 401, Paragraph 45; M. pp. 336, 258.) Hence we subscribe to the statement of our Confessions that the Pope is “the very Antichrist.” (Smalcald Articles, Triglot, p. 475, Paragraph 10; M., p. 308.) *
lcms.org/doctrine/doctrinalposition#antichrist
It was a real question and I tried to answer it honestly and I do expect roils of indignation to follow this link, but please bear in mind that we generally regard our Catholic brethren as brethren and the Catholic Church as a Christian Church. We don’t spew hatred of Catholicism ( that would be considered very offensive to the Italian and Irish converts to Lutheranism we have at my parish and I can think of at least one person of Scotch- Irish predilections and a French Cajun great- grandmother who attends our divine service and would find any kind of demonization of Catholics to be
highly offensive. He has kind of a big mouth and would be very vocal in his objections) and right now, the polemic is directed primarily against Islam…